Date: Fri, 10 Sep 2010 11:50:32 +0300 From: App Deb <appdebgr@gmail.com> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: freebsd-fs@freebsd.org Subject: Re: Swap on ZFS Volume still panics? Message-ID: <AANLkTin_Cm=EebQ9HV9r=-=CN2S7oCyyme%2BLZ2f5z5zs@mail.gmail.com> In-Reply-To: <20100910073912.GC2007@garage.freebsd.pl> References: <AANLkTin4DAY%2BWXOpckWJCs437BGg0mjAFzRv%2BiDEG-F1@mail.gmail.com> <20100910073912.GC2007@garage.freebsd.pl>
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Yes sorry for actually calling it a panic, it is a deadlock, I didn't see any messages, anyway the system becomes unusable and needs a manual hard reboot. I found the mention (without any warnings) here: http://wiki.freebsd.org/RootOnZFS I have tried this on 3 different systems (all 8.1R though) and they always deadlock once the zfs swap is touched. I think that the "not recommended" is not enough. It just doesn't work at all, except if I am doing something wrong and there are some cases that it works? I have now switched to native freebsd-swap (after a long zfs send/receive backup to resize the zpool :) ) and everything works great. Thanks. On Fri, Sep 10, 2010 at 10:39 AM, Pawel Jakub Dawidek <pjd@freebsd.org>wrote: > On Wed, Sep 08, 2010 at 07:19:40PM +0300, App Deb wrote: > > Reading the wiki guides they mention the official way to add swap volumes > on > > ZFS (set org.freebsd:swap=on etc..), > > > > So I thought that it should work now, But I just got a panic in > 8.1-RELEASE > > after a heavy memory situation that touched swap for the first time. > > Swap on ZVOL is still not recommended. Where did you find information > that it now recommended? I can't find anything about swap on > http://wiki.freebsd.org/ZFS and on > http://wiki.freebsd.org/ZFSQuickStartGuide there is a note that it is > not recommended. Let me know where it is advised and I'll remove it or > add a note (if the documentation is mine). > > > It is a hassle to add gmirror volumes for swap on full zfs systems, is > there > > any workaround for this, or any news when a fix is coming or if it is > > coming? > > I've no plans to fix it, maybe with ZFSv28 it will be easier to fix, but > this is really low priority. If you use full ZFS system the recommended > layout is described here: > > > http://blogs.freebsdish.org/pjd/2010/08/06/from-sysinstall-to-zfs-only-configuration/ > > > If the current code procudes guaranteed panics with zfs swap, I think > that > > every mention of swap on zfs should be removed from the semi-official > wiki > > guides. > > BTW. If this issue will be worked on in the future, it will be useful to > actually see your panic, backtrace and other debug info. To be honest, I > didn't expect it to panic, rather deadlock. Maybe panic is from deadlock > resolver? Hard to say without any debug info. > > -- > Pawel Jakub Dawidek http://www.wheelsystems.com > pjd@FreeBSD.org http://www.FreeBSD.org > FreeBSD committer Am I Evil? Yes, I Am! >
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